optima D

I cant find any real info about this rx.
only this:
The Hitec OPTIMA D is a compact and practical micro size 2.4GHz receiver perfect for drones and especially Racing Drone, with its voltage telemetry capability.
Selectable S-Bus/PPM signal provides compatibility with any type of Flight Controller in the market.
The Hitec OPTIMA D is suitable for all racing drone pilots with 2.4GHz Hitec radios.

Can i use this on 500 size heli with MSH Brain FBL. is this sbus compatible? How many chanels?

We've only had a few to test here in our office but the theory is that it should work fine. The receiver will output the full 9 channels, but for helicopter purposes you would be better off with a Maxima SL receiver if you are using an Aurora 9X. If you are using an Aurora 9 then it should be fine, though the antennas are short.

More info??

I'm also interested to know more about this optima D receiver.

I use an aurora 9 tx, and an old JR9303 with a hitec spectra module in it. I'd love to know what the safe range on the optima D is. I've been scouring the internet for hours and haven't been able to find any useful information. Even Hitec's own website is super vague.

I've got 6 frsky minima compatible receivers that I use instead.

C'mon hitec, give us some help/info on your products, you're loosing a stack of sales because no-one knows what does what!

I bought an optima D to test it out. 1.4km range on the ground with an A9 tx. Its finicky when binding, it needs to be much closer to the tx than other receivers. This is mentioned in the manual, but it still took me several attempts to get a link. Not a problem, but worth mentioning if you're in the habit of binding a couple of metres away (frsky minima style). The manual is as vague as any other hitec manual. All of the relevant information is there, just read it carefully and you'll be fine.

Bought two of these to use on my race quads as soon as they were available.

Definitely an upgrade compared to any previous RX from hitec, tailored for drone racing with direct support for low latency simple interfaces like PPM and s.bus. Cheap, small, light. I immediately started flying much much better with the far lesser lag I now have with direct s.bus connection compared to my previous setup of: optima 6 lite PWM -> PPM encoder -> FC.

However... there is a flaw in this RX, a HUGE flaw.

Who on earth thought it was a good idea to cram in both antenna connectors tightly sandwiched between two hard soldered PCBs making it efficiently almost impossible to replace the antennas... on a RX designed for drone racing where you get antennas cut off from time to time... seriously?

So, for now, my suggestion for anyone using this receiver is to not prioritize range when mounting the antennas but rather durability.
Try to hide and protect the antennas as good as possible on your models because it might be the only ones you get with this great risk of breaking the RX if you have to try replacing them.

That is a good observation! Are the boards soldered together? That is a bit silly. Would it be possible for someone with good soldering skills to separate the boards?

It is possible to reflash your optima 6 and 7 receivers to output ppm.
I've done it to one of mine and it works perfect. Its not difficult to do if you have some experience with atmel chips.

Soldered on both sides, very hard to separate. My friend who is really good at soldering managed to separate them just enough to rip out antennas and get in new ones after many minutes of swearing tho. But it was risky, we weren't sure if the receiver was still working afterwards, but it seems to have survived luckily.

I read about PPM mods on other receivers but I could never get confirmation if it worked on optima 6 lite or if the voltage telemetry from the receiver was still working after that and that would be a deal breaker for me so I never tried it. It worked pretty ok with a PPM encoder anyway.
If no telemetry, you might as well buy the cheap hitec compatible receivers with PPM from hobbyking.

In this case tho its the s.bus that is of significant and has much lower latency than PPM.

There's 2 processors in the receiver. One that can be updated with the hp22 unit, responsible for rf and telemetry protocol. The other responsible for generating servo commands. It has pins outputting all 9 channels, even in the 6 and 7 channel receivers. Chances are someone smarter than me could probably write S-bus code for it. I'm still pretty happy with the ppm mod

For some reason fail-safe refuse to work on it, even tho it behaves exactly like the manual suggest and should have saved the current signal from transmitter it completely ignores it and acts as if there is no fail-safe when I turn off my transmitter.

example: Holding button 6 seconds while my quad is disarmed I release see the blue led flashing, more rapidly and then turning solid, should indicate fail-safe saved as it is now.
I place quad on floor, flip switch to arm it, props spinning neutral, turn off my radio. nothing at all happens, it stays armed, even after 20sec it still didn't react.

Not sure if it has something to do with s.bus connection or something else is wrong.

Update: Further investigations show that the RX at least starts to flash after TX is turned off to indicate it lost signal.
Next step is to investigate if the error might lies in the FC or if the RX doesn't change to fail-safe settings when loosing signal.

Update 2: Seem the RX at least indicated it was in fail-safe mode even tho it didn't apply the settings so applying fail-safe setting from flight controler worked fine. Still suspect that has something to do with it being connected on s.bus in this case.